Should I call the pediatrician?

My 3 month old is currently sick with what I thought was a cold but now I’m not so sure.

His symptoms are:

Difficulty breathing for a few seconds when mucus drains

Coughing

Vomiting up mucus

Sneezing

Congestion

Low grade fever

Refusing to eat/gagging when eating

Breathing from mouth

He’s a NICU baby so I’ve had to call his pediatrician a lot. I just don’t want them thinking I’m overreacting. I can’t help but worry because he’s been sick for days. He’s a happy baby but I can tell he feels bad.